ftrace: Have global_ops store the functions that are to be traced
This is a step towards each ops structure defining its own set
of functions to trace. As the current code with pid's and such
are specific to the global_ops, it is restructured to be used
with the global ops.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 8fef1d9..dcce0bf 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -91,6 +91,7 @@
ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
+static struct ftrace_ops global_ops;
/*
* Traverse the ftrace_list, invoking all entries. The reason that we
@@ -153,7 +154,7 @@
}
#endif
-static void update_ftrace_function(void)
+static void update_global_ops(void)
{
ftrace_func_t func;
@@ -173,6 +174,18 @@
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
+
+ global_ops.func = func;
+}
+
+static void update_ftrace_function(void)
+{
+ ftrace_func_t func;
+
+ update_global_ops();
+
+ func = global_ops.func;
+
#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
ftrace_trace_function = func;
#else
@@ -181,17 +194,51 @@
#endif
}
-static int __register_ftrace_function(struct ftrace_ops *ops)
+static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
{
- ops->next = ftrace_list;
+ ops->next = *list;
/*
* We are entering ops into the ftrace_list but another
* CPU might be walking that list. We need to make sure
* the ops->next pointer is valid before another CPU sees
* the ops pointer included into the ftrace_list.
*/
- rcu_assign_pointer(ftrace_list, ops);
+ rcu_assign_pointer(*list, ops);
+}
+static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
+{
+ struct ftrace_ops **p;
+
+ /*
+ * If we are removing the last function, then simply point
+ * to the ftrace_stub.
+ */
+ if (*list == ops && ops->next == &ftrace_list_end) {
+ *list = &ftrace_list_end;
+ return 0;
+ }
+
+ for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
+ if (*p == ops)
+ break;
+
+ if (*p != ops)
+ return -1;
+
+ *p = (*p)->next;
+ return 0;
+}
+
+static int __register_ftrace_function(struct ftrace_ops *ops)
+{
+ if (ftrace_disabled)
+ return -ENODEV;
+
+ if (FTRACE_WARN_ON(ops == &global_ops))
+ return -EINVAL;
+
+ add_ftrace_ops(&ftrace_list, ops);
if (ftrace_enabled)
update_ftrace_function();
@@ -200,27 +247,17 @@
static int __unregister_ftrace_function(struct ftrace_ops *ops)
{
- struct ftrace_ops **p;
+ int ret;
- /*
- * If we are removing the last function, then simply point
- * to the ftrace_stub.
- */
- if (ftrace_list == ops && ops->next == &ftrace_list_end) {
- ftrace_trace_function = ftrace_stub;
- ftrace_list = &ftrace_list_end;
- return 0;
- }
+ if (ftrace_disabled)
+ return -ENODEV;
- for (p = &ftrace_list; *p != &ftrace_list_end; p = &(*p)->next)
- if (*p == ops)
- break;
+ if (FTRACE_WARN_ON(ops == &global_ops))
+ return -EINVAL;
- if (*p != ops)
- return -1;
-
- *p = (*p)->next;
-
+ ret = remove_ftrace_ops(&ftrace_list, ops);
+ if (ret < 0)
+ return ret;
if (ftrace_enabled)
update_ftrace_function();
@@ -894,7 +931,7 @@
FTRACE_OPS_FL_ENABLED = 1,
};
-struct ftrace_ops global_ops = {
+static struct ftrace_ops global_ops = {
.func = ftrace_stub,
.notrace_hash = EMPTY_HASH,
.filter_hash = EMPTY_HASH,
@@ -3263,7 +3300,7 @@
#else
-struct ftrace_ops global_ops = {
+static struct ftrace_ops global_ops = {
.func = ftrace_stub,
};